Peptide delivery to tissues via reversibly linked protein transduction sequences.

The development of peptide-based therapeutics has suffered from challenges associated with delivery to intact tissue. In skin, an array of protein targets resides only tens of micrometers below the surface; however, because of difficulties in traversing the cutaneous barrier, the potentialfor peptide-based therapeutics remains unrealized. We have developed a general approach for topical peptide delivery into skin using releasable protein transduction sequences to enable peptide transport across tissue boundaries. Upon entry into the cell, the disulfide linkage between the peptide transduction sequences and peptide cargo is cleaved, permitting the dissociation of the highly charged peptide transduction sequences from the active peptide. A protype cargo peptide, the hemagglutinin (HA) epitope, was conjugated to a hepta-arginine protein transduction sequence via a releasable disulfide linkage. This construct penetrated the skin to deep dermis within 1 h after topical application. Consistent with the dissociation of the protein transduction and cargo sequences, absorbed protein transduction sequences and HA peptides displayed differential intracellular localization. Reversible protein transduction sequence linkage thus represents a noninvasive platform for tissue delivery of intact peptides with no requirement for viral vectors or parenteral injection and may be of broad utility in molecular therapy.